There are a number of known methods of smelting iron ore and partly reduced iron ore which are based on the use of a metallurgical vessel (often referred to as a "smelt reduction vessel") containing a molten bath of iron and slag.
In general terms, these known methods require that a carbonaceous material be injected into the molten bath as a source of reductant and thermal energy. The carbonaceous material may be in solid form, such as coal, or in gaseous form, such as natural gas.
Australian patent 649,402 entitled "Smelting of Pre-reduced Iron Oxide" in the name of Zurich Branch of Midrex International BV Rotterdam discloses one particular method of smelting iron ore and partly reduced iron ore which is based on the injection of natural gas into a molten bath in a metallurgical vessel.